Our look is the result of reader comments, our own experimentation, and feedback from distribution channels. Distinctive covers complement our distinctive approach to technical topics, breathing personality and life into potentially dry subjects. The animal on the cover of SpamAssassin is a King vulture. King vultures (Sarcoramphus papa) are found in tropical lowland forests from Mexico to Argentina. Vultures serve a useful purpose in disposing of dead and decaying animal remains.

Their extremely thick and strong bills are well adapted for tearing, as are their long, thick claws for holding meat. King vultures have a very heavy beak, a necessary asset for tearing into large, thick-skinned animals. The absence of feathers on a vulture's head helps the bird "clean up" after a messy meal.

King vultures do not build nests. The female simply deposits her single egg in the hollow of a rotten tree trunk or in a crack caused by age or lightning. Both parents take turns incubating the egg. When hatched, King vulture chicks have no feathers, but soon are covered with a white down. They do not acquire their adult plumage until they are 18 months old.

While they have very keen eyesight, King vultures have a poor sense of smell. They often rely on other vulture species to locate food. Much larger and stronger than other vultures, the King vulture is useful to the others because it is capable of tearing open tough skin. When other vultures have found carrion, a King vulture or two often arrive and immediately dominate the carcass--hence the name "King."

King vultures will sometimes glide in wide circles for long periods, spying on their domain below and searching for food. By making perfect use of the air currents, vultures are able to soar for hours at a time, without once flapping their wings. Darren Kelly was the production editor, Nancy Crumpton was the copyeditor, and Jan Fehler was the proofreader for SpamAssassin. Reg Aubry and Claire Cloutier provided quality control. Nancy Crumpton provided production services and wrote the index.

Ellie Volckhausen designed the cover of this book, based on a series design by Edie Freedman. The cover image is a 19th-century engraving from the Dover Pictorial Archive. Emma Colby produced the cover layout with QuarkXPress 4.1 using Adobe's ITC Garamond font.

Melanie Wang designed the interior layout, based on a series design by David Futato. This book was converted by Andrew Savikas to FrameMaker 5.5.6 with a format conversion tool created by Erik Ray, Jason McIntosh, Neil Walls, and Mike Sierra that uses Perl and XML technologies. The text font is Linotype Birka; the heading font is Adobe Myriad Condensed; and the code font is LucasFont's TheSans Mono Condensed. The illustrations that appear in the book were produced by Robert Romano and Jessamyn Read using Macromedia FreeHand 9 and Adobe Photoshop 6. The tip and warning icons were drawn by Christopher Bing. This colophon was written by Darren Kelly.